Valley Falls, OR

Located in south-central Oregon, the Abert (pronounced “AY-bert”) Rim is said to be the longest exposed fault scarp in the United States, at some 30 miles in extent. It’s also one of the highest, with around 2,500 feet of relief. The rim is topped with a thick (>800 feet) sequence of basalts that commonly forms a prominent dark capping cliff. These basalts are part of the extensive basalt eruptions centered around Steens Mountain some 80 miles east.

The Abert Rim is paralleled by US-395 on the west for most of its length. The rim was formed by crustal extension due to Basin and Range faulting, which extends into Oregon here. The faulting has occurred within the last ten million years or so.

The rim is spectacular from below, but also provides breathtaking views from its crest. One of the easiest access points to the crest, sometimes called Tague’s Butte after a hang-gliding enthusiast who popularized it, is near the southern end. As might be expected, this point is also a popular site for hang-glider launches.

The Abert Rim (and nearby Abert Lake) were named for John James Abert by explorer John C. Frémont, who came through this area in 1843. Abert was the head of the Corps of Topographical Engineers, which carried out explorations in the west before the U.S. Civil War, and he had authorized Frémont’s expedition.